Catalysts

ABSTRACT

The invention describes ligands of formula (I), wherein LIG represents an η 5 -ligand substituted by a group R 1  and a group (R″) m ; X represents a 1 to 3 atom bridge; Y represents a nitrogen or phosphorus atom; Z represents a carbon, nitrogen or phosphorus atom.

[0001] This invention relates to catalysts for olefin polymerisation, inparticular to catalyst compounds containing metals η-bonded byη⁵-ligands, e.g. cyclopentadienyl ligands and η or σ-bonded by abicyclic nitrogen ligand, and their use in olefin polymerisation.

[0002] In olefin polymerization, it has long been known to use as acatalyst system the combination of a metallocene procatalyst and analumoxane or boron based co-catalyst.

[0003] By “metallocene” is here meant an η-ligand metal complex, e.g. an“open sandwich” or “half sandwich” compound in which the metal iscomplexed by a single η-ligand, a “sandwich” compound in which the metalis complexed by two or more η-ligands, a “handcuff” compound” in whichthe metal is complexed by a bridged bis-η-ligand or a “scorpionate”compound in which the metal is complexed by an η-ligand linked by abridge to a σ-ligand.

[0004] Metallocene procatalysts are generally used as part of a catalystsystem which also includes an ionic cocatalyst or catalyst activator,for example, an aluminoxane (e.g. methylaluminoxane (MAO),hexaisobutylaluminoxane and tetraisobutylaluminoxane) or a boroncompound (e.g. a fluoroboron compound such as triphenylpentafluoroboronor triphentylcarbenium tetraphenylpentafluoroborate ((C₆H₅)₃B⁺B⁻(C₆F₅)₄))

[0005] Alumoxanes are compounds with alternating aluminium and oxygenatoms generally compounds of formula

[0006] where each R, which may be the same or different, is a C₁₋₁₀alkyl group, and p is an integer having a value between 0 and 40). Thesecompounds may be prepared by reaction of an aluminium alkyl with water.The production and use of alumoxanes is described in the patentliterature, especially the patent applications of Texas Alkyls,Albemarle, Ethyl, Phillips, Akzo Nobel, Exxon, Idemitsu Kosan, Witco,BASF and Mitsui.

[0007] Traditionally, the most widely used alumoxane is methylalumoxane(MAO), an alumoxane compound in which the R groups are methyls. MAOhowever is poorly characterised and relatively expensive and effortshave been made to use alumoxanes other than MAO. Thus, for exampleWO98/32775 (Borealis) proposes the use of metallocene procatalysts withalumoxanes in which R is a C₂₋₁₀ alkyl group, eg hexaisobutylalumoxane(HIBAO). However, such metallocenes generally have poor catalystactivities with non-MAO alumoxanes.

[0008] Since each polymerisation catalyst gives rise to polymer productswith slightly differing properties, there remains an ongoing search fornew and improved olefin polymerisation catalysts.

[0009] We have now surprisingly found that a single site procatalystsystem based on a η⁵-ligand, e.g. cyclopentadienyl type ligand and a ηor σ-bonding bicyclic nitrogen ligand may be used very effectively inpolymerisation catalysis, especially in the manufacture of polyethyleneor polypropylene.

[0010] Thus viewed from one aspect the invention provides a compound offormula (I) comprising

[0011] wherein

[0012] LIG represents an η⁵-ligand substituted by a group R₁ and a group(R″)_(m);

[0013] X represents a 1 to 3 atom bridge, optionally substituted, e.g.by R″ groups;

[0014] Y represents a nitrogen or phosphorus atom;

[0015] Z represents a carbon, silicon, nitrogen or phosphorus atom;

[0016] the ring denoted by A₁ is an optionally substituted, optionallysaturated or unsaturated 5 to 12 membered heterocyclic ring;

[0017] the ring denoted by A₂ is an optionally substituted, unsaturated5 to 12 membered heterocyclic ring;

[0018] R₁ represents hydrogen, R″ or a group OSiR′₃;

[0019] each R′, which may be the same or different is a R⁺, OR⁺, SR⁺,NR⁺ ₂ or PR⁺ ₂ group where each R⁺ is a C₁₋₁₆ hydrocarbyl group, atri-C₁₋₈hydrocarbylsilyl group or a tri-C₁₋₈hydrocarbylsiloxy group,preferably R′ being a C₁₋₁₂ hydrocarbyl group, e.g. a C₁₋₈ alkyl oralkenyl group;

[0020] each R″, which may be the same or different is a ring substituentwhich does not form a σ-bond to a metal η-bonded by the bicyclic ring,eg it may be hydrogen, R⁺, OR⁺, SR⁺, NR⁺ ₂ or PR⁺ ₂ group where each R⁺is a C₁₋₁₆ hydrocarbyl group, a tri-C₁₋₈ hydrocarbylsilyl group or atri-C₁₋₈hydrocarbylsiloxy group; and

[0021] m is zero or an integer between 1 and 3.

[0022] Viewed from a further aspect the invention provides an olefinpolymerisation catalyst system comprising or produced by reaction of (1)a metallated compound as hereinbefore defined (from hereon called aprocatalyst) and (2) a cocatalyst, e.g. an aluminium alkyl compound orboron compound, in particular an alumoxane, especially an aluminiumalkyl compound comprising alkyl groups containing at least two carbonatoms.

[0023] Viewed from a still further aspect the invention provides aprocess for olefin polymerisation comprising polymerising an olefin inthe presence of a catalyst system as hereinbefore described.

[0024] Viewed from a yet further aspect the invention provides a processfor the preparation of a procatalyst, said process comprisingmetallating with a group 3 to 7 transition metal a compound of formula(I)

[0025] wherein LIG, X, Y, Z and rings A₁ and A₂ are as hereinbeforedefined.

[0026] Viewed from a further aspect the invention provides the use of aprocatalyst as hereinbefore defined in olefin polymerization, especiallyethylene or propylene polymerisation or copolymerisation.

[0027] Viewed from a yet further aspect the invention provides an olefinpolymer produced by a polymerisation catalysed by a procatalyst compoundas hereinbefore defined.

[0028] The compounds of formula (I) as hereinbefore described may becoupled with a metal from groups 3 to 7. By group 3 (etc) metal is meanta metal in group 3 of the Periodic Table of the Elements, namely Sc, Y,etc. It is preferable if the metal coupling the compound of theinvention is in the III⁺ oxidation state, although metals in the II⁺ andIV⁺ oxidation states are also advantageous. The metal employed in thecatalyst system of the invention is most preferably from groups 4, 5 or6 of the periodic table, e.g. Cr, Mo, W, Ti, Zr, Hf, V, Nb or Ta. Mostespecially the metal is Cr or Ti, e.g. Cr³⁺ or Ti³⁺.

[0029] Where the metal is Cr, it has surprisingly been found that thecatalyst system of the invention is capable of making polypropylene as apowder.

[0030] The group 3 to 7 metal in the metallated procatalyst of theinvention coordinates to the η⁵-ligand and σ or η bonds to certain atomsin the bicyclic nitrogen ligand. Where the metal forms sigma bonds withthe bicyclic nitrogen ligand, only atoms Z and N can coordinate to themetal. Thus, the metal may be coordinated only to atom X, only to N orto both the Z and N atoms. The Y atom is therefore not involved incoordination with the metal.

[0031] However, if an η ligand is formed between the metal and bicyclicnitrogen group then coordination to any double bond present in bicyclicnitrogen ligand is possible. Such η bonds may be η² or η³ depending onthe nature of the bicyclic nitrogen ligand. The metal may also becoordinated by hydrogen atoms, hydrocarbyl σ-ligands (eg optionallysubstituted C₁₋₁₂ hydrocarbyl groups, such as C₁₋₁₂ alkyl, alkenyl oralkynyl groups optionally substituted by fluorine and/or aryl (egphenyl) groups), by silane groups (eg Si(CH₃)₃), by halogen atoms (egchlorine), by C₁₋₈ hydrocarbylheteroatom groups, bytri-C₁₋₈hydrocarbylsilyl groups, by bridged bis-σ-liganding groups, byamine (eg N(CH₃)₂) or imine (eg N═C or N═P groups, eg (iPr)₃P═N) groups,or by other σ-ligands known for use in metallocene (pro) catalysts.

[0032] By a σ-ligand moiety is meant a group bonded to the metal at oneor more places via a single atom, eg a hydrogen, halogen, silicon,carbon, oxygen, sulphur or nitrogen atom.

[0033] Examples of σ-ligands include

[0034] halogenides (e.g. chloride and fluoride), hydrogen,

[0035] triC₁₋₁₂ hydrocarbyl-silyl or -siloxy(e.g. trimethylsilyl),

[0036] triC₁₋₆ hydrocarbylphosphimido (e.g. triisopropylphosphimido),

[0037] C₁₋₁₂hydrocarbyl or hydrocarbyloxy (e.g. methyl, ethyl, phenyl,benzyl and methoxy),

[0038] diC₁₋₆ hydrocarbylamido (e.g. dimethylamido and diethylamido),and

[0039] 5 to 7 ring membered heterocyclyl (eg pyrrolyl, furanyl andpyrrolidinyl). Preferable σ ligands include halogens, alkyls, orchloro-amido groups.

[0040] Y preferably represents a nitrogen atom.

[0041] In the catalyst system formed from the compound of the invention,the Y atom does not sigma coordinate to the metal ion. Instead, the atomat Y serves to provide an atom whereby the bridging group X can join thebicyclic nitrogen group to the η⁵-ligand.

[0042] The Z atom, which as mentioned above may be involved incoordination with the metal ion, is preferably a phosphorus or nitrogenatom, especially a nitrogen atom.

[0043] In a most preferred embodiment both Y and Z are nitrogen.

[0044] The A rings (A₁ and A₂), formed partially from the atoms —Y—C—Z—or —N—C—Z— may be or different sizes but are preferably or the samesize. Moreover, each ring preferably has either 5 or 6 members. Whilstthe rings may contain further heteroatoms selected from N, P, S or B,this is not preferred. Thus, apart from the potential heteroatomsrepresented by Y and Z, the A rings are preferably formed from carbonatoms. The A rings may contain double bonds and may be aromatic butpreferably the rings contain no double bonds in addition to the doublebond which must be present between the C and N in formula (I).Preferably, the rings are unsubstitued.

[0045] Thus suitable bicyclic groups include those illustrated below.

[0046] In a highly preferred embodiment the bicyclic group is formedfrom two fused six membered rings and Y and Z are nitrogen, i.e. thelast or the five structures above.

[0047] The η⁵-ligand may be any η⁵-ligand which forms an η-bond with thecomplexing metal ion. Suitable ligands therefore includedipyridylmethanyl, indenyl, fluorenyl or cyclopentadienyl ligands. Theη⁵-ligand is substituted by groups R₁ and (R″)_(m) as hereinbeforedefined. Hence, suitable procatalysts or use in the invention includethose of formula

[0048] wherein R₁, R″, m, X, Y, Z and rings A₁ and A₂ are ashereinbefore defined. Alternatively, the η⁵-ligand is of formula

[0049] wherein R₁, R″, m, X, Y, Z and rings A₁ and A₂ are ashereinbefore defined. In the above formula, the R₁ and R″ groups may bebound to any ring of the η⁵-ligand, i.e. although the R₁ group in theformula immediately above is depicted as being generally present on the5-membered ring, the nomenclature is intended to cover the possibilityor the R₁ group being present on the 6-membered ring.

[0050] The preferred nature of the groups R₁ and R″ varies depending onthe nature or the η⁵-ligand. Where the η⁵-ligand is a cyclopentadienyl,R₁ is preferably a group of formula OSiR′₃. Preferably R′ is a C₁₋₁₂hydrocarbyl group, e.g. a C₁₋₁₈ alkyl or alkenyl group, especiallymethyl or isopropyl.

[0051] Examples of suitable R′₃SiO groups in the compounds orprocatalysts of the invention include

[0052] Where the η⁵-ligand is a cyclopentadienyl group, the OSiR′₃ groupmay be situated at any position on the cyclopentadienyl ring butpreferably is alpha to the carbon atom involved in bridging.

[0053] The cyclopentadienyl group itself may be substituted by up tothree groups R″ and R″ preferably represents C₁₋₁₆ alkyl, especiallymethyl. In a highly preferred embodiment, three R″ groups are presentand R″ is methyl. Since R₁ may also represent R″ a cyclopentadienylsubstituted by four methyl groups is also within the scope of theinvention.

[0054] Also within the scope of the invention are cyclopentadienylgroups wherein one of the carbon atoms not bound to the bridging group Xor if present the OSiR′₃ group, is replaced by a heteroatom selectedfrom phosphorus, silicon, nitrogen or boron. It is stressed however,that preferably there are no heteratoms present in the cyclopentadienylring.

[0055] Thus typical examples or suitable cyclopentadienyl type moietiesinclude:

[0056] Examples of particular cyclopentadienyl siloxy groups usableaccording to the invention include:

[0057] triisopropylsiloxycyclopentadienyl,

[0058] 1-triisopropylsiloxy-3-methyl-cyclopentadienyl,

[0059] 1-triisopropylsiloxy-3,4-dimethyl-cyclopentadienyl,

[0060] 1-triisopropylsiloxy-2,3,4-trimethyl-cyclopentadienyl,

[0061] (dimethyltertbutylsiloxy)-cyclopentadienyl,

[0062] 1-(dimethyltertbutylsiloxy)-3-methylycyclopentadienyl,

[0063] 1-(dimethyltertbutylsiloxy)-3,4-dimethylcyclopentadienyl,

[0064] 1-(dimethyltertbutylsiloxy)-2,3,4-trimethyl-cyclopentadienyl,

[0065] 1-triisopropylsiloxy-2-phospholyl,

[0066] 1-triisopropylsiloxy-3-phospholyl,

[0067] 1-dimethyltertbutylsiloxy-2-phospholyl,

[0068] 1-dimethyltertbutylsiloxy-3-phospholyl,

[0069] 1-triisopropylsiloxy-2-borolyl,

[0070] 1-triisopropylsiloxy-3-borolyl,

[0071] 1-dimethyltertbutylsiloxy-2-borolyl,

[0072] 1-dimethyltertbutylsiloxy-3-borolyl,

[0073] 1-(dimethyloct-1-en-8-ylsiloxy)-3-methyl-cyclopentadienyl,

[0074] 1-(dimethyloct-1-en-8-ylsiloxy)-3,4-dimethyl-cyclopentadienyl.

[0075] Where the η⁵-ligand is a dipyridylmethanyl, indenyl or fluorenylspecies the R₁ may also be a group of formula OSiR′₃ as hereinbeforedescribed but preferably R₁ is hydrogen. R″ may represent a C₁₋₆ alkyl,especially methyl but again in a preferred embodiment R″ is hydrogen.Where the η ligand is indenyl, R″ may preferably represent an n-alkenyl,e.g. n-hexyl.

[0076] Examples of particular further η-ligands are well known from thetechnical and patent literature relating to metallocene olefinpolymerization catalysts, e.g. EP-A-35242 (BASF), EP-A-129368 (Exxon),EP-A-206794 (Exxon), PCT/FI97/00049 (Borealis), EP-A-318048,EP-A-643084, EP-A-69951, EP-A-410734, EP-A-128045, EP-B-35242 (BASF),EP-B-129368 (Exxon), WO97/23493, Organometallics 1995, 14, 471 andEP-B-206794 (Exxon). Further suitable η-ligands are those or formula

[0077] The bridging group X is preferably a one or two atom bridgecomprising silicon or carbon. The bridge preferably connects to a carbonatom present in the 5-membered ring or the η⁵-ligand. However, where theligand comprises a heteroatom such as boron, the bridge may attach tothe heteroatom or to the heteroatom's substituents. Where the bridge isformed from silicon, the bridge may be of formula —Si(R₂)₂ wherein eachR₂ independently represents a C₁₋₁₀ alkyl, C₁₋₁₀ alkenyl, aryl, e.g.phenyl, trimethylsilyl, or both R₂ groups taken together may form aring, e.g. five membered ring, with the Si. Where the bridge comprisescarbon, the bridge is preferably a one atom bridge, e.g. —CH₂— or—CH(CH₃)₂—. Suitable bridges are depicted below

[0078] In a highly preferred embodiment, compound according to theinvention is of formula

[0079] wherein R′, m and R″ are as hereinbefore described.

[0080] Further typical examples of the procatalysts or the inventioninclude:

[0081] The procatalysts of the invention may be prepared by conventionaltechniques which will be readily devised by the person skilled in theart. Conveniently for example, the procatalyst is constructed bycombining the bicyclic ligand with, for example, the siloxycyclopentadienyl ligand followed by subsequent metallation. The bridginggroup may be carried by either the bicyclic ligand or thecyclopentadienyl ligand but conveniently the bridging group is attachedto the bicyclic group first.

[0082] Where the bicyclic group is for example1.5.7-triaza[4.4.0]bicyclo-dec-5-ene this may be deprotonated by astrong base and the resulting anion reacted with a bridging group suchas dimethylsilyldichloride. The cyclopentadienyl η-ligands usedaccording to the invention may be prepared by reaction of acorresponding siloxycyclopentadiene with an organolithium compound, egmethyllithium or butyllithium. The reaction or the lithiumcyclopentadienyl species with the bicyclic ligand carrying bridiginggroup gives rise to a compound or the invention after furtherdeprotonation. These reactions are depicted in the Scheme below.

[0083] Fluorenyl and indenyl compounds of the invention may be preparedby analogous techniques to those required to prepare thecyclopentadienyl compounds.

[0084] Where the η-ligand is a dipyridylmethanediyl, the bicyclicnitrogen ligand may be reacted with a species generated as illustratedin the following scheme.

[0085] Deprotonation of the product again leaves the compound of theinvention. The starting material may be functionalised as necessary tohave required substituents using conventional synthetic chemistry. It isof course possible to have the dipyridylmethanediyl carry the bridginggroup using the following chemistry:

[0086] The compound can be metallated conventionally, eg by reactionwith a halide or the metal M, preferably in an organic solvent, eg ahydrocarbon or a hydrocarbon/ether mixture.

[0087] σ-ligands other than chlorine may be introduced by displacementor chlorine from an η-ligand metal chloride by reaction with appropriatenucleophilic reagent (e.g. methyl lithium or methylmagnesium chloride)or using, instead or a metal halide, a reagent such astetrakisdimethylamidotitanium or metal compounds with mixed chloro anddimethylamido ligands.

[0088] As mentioned above, the olefin polymerisation catalyst system ofthe invention comprises (i) a procatalyst formed from a metallatedcompound of formula (I) and (ii) an aluminium alkyl compound, or thereaction product thereof. While the aluminium alkyl compound may be analuminium trialkyl (eg triethylaluminium (TEA)) or an aluminium dialkylhalide (eg diethyl aluminium chloride (DEAC)), it is preferably analumoxane, particularly an alumoxane other than MAO, most preferably anisobutylalumoxane, eg TIBAO (tetraisobutylalumoxane) or HIBAO(hexaisobutylalumoxane). Alternatively however the alkylated (egmethylated) metallocene procatalysts of the invention (e.g. compounds orformula V wherein Z is alkyl) may be used with other cocatalysts, egboron compounds such as B(C₆F₅)₃, C₆H₅N(CH₃)₂H:B(C₆F₅)₄,(C₆H₅)₃C:B(C₆F₅)₄ or Ni (CN)₄[B(C₆F₅)₃]₄ ²—.

[0089] The metallocene procatalyst and cocatalyst may be introduced intothe polymerization reactor separately or together or, more preferablythey are pre-reacted and their reaction product is introduced into thepolymerization reactor.

[0090] If desired the procatalyst, procatalyst/cocatalyst mixture or aprocatalyst/cocatalyst reaction product may be used in unsupported formor it may be precipitated and used as such. However the metalloceneprocatalyst or its reaction product with the cocatalyst is preferablyintroduced into the polymerization reactor in supported form, egimpregnated into a porous particulate support.

[0091] The particulate support material used is preferably an organic orinorganic material, e.g. a polymer(such as for example polyethylene,polypropylene, an ethylene-propylene copolymer, another polyolefin orpolystyrene or a combination thereof). Such polymeric supports may beformed by precipitating a polymer or by a prepolymerization, eg ofmonomers used in the polymerization for which the catalyst is intended.However, the support is especially preferably a metal or pseudo metaloxide such as silica, alumina or zirconia or a mixed oxide such assilica-alumina, in particular silica, alumina or silica-alumina.Particularly preferably, the support material is acidic, e.g. having anacidity greater than or equal to silica, more preferably greater than orequal to silica-alumina and even more preferably greater than or equalto alumina. The acidity of the support material can be studied andcompared using the TPD (temperature programmed desorption or gas)method. Generally the gas used will be ammonia. The more acidic thesupport, the higher will be its capacity to adsorb ammonia gas. Afterbeing saturated with ammonia, the sample or support material is heatedin a controlled fashion and the quantity of ammonia desorbed is measuredas a function of temperature.

[0092] Especially preferably the support is a porous material so thatthe metallocene may be loaded into the pores of the support, e.g. usinga process analogous to those described in WO94/14856 (Mobil), WO95/12622(Borealis) and WO96/00243 (Exxon). The particle size is not critical butis preferably in the range 5 to 200 μm, more preferably 20 to 80 μm.

[0093] Before loading, the particulate support material is preferablycalcined, ie heat treated, preferably under a non-reactive gas such asnitrogen. This treatment is preferably at a temperature in excess or100° C., more preferably 200° C. or higher, e.g. 200-800° C.,particularly about 300° C. The calcination treatment is preferablyeffected for several hours, e.g. 2 to 30 hours, more preferably about 10hours.

[0094] The support may be treated with an alkylating agent before beingloaded with the metallocene. Treatment with the alkylating agent may beeffected using an alkylating agent in a gas or liquid phase, e.g. in anorganic solvent for the alkylating agent. The alkylating agent may beany agent capable of introducing alkyl groups, preferably C₁₋₁₆ alkylgroups and most especially preferably methyl groups. Such agents arewell known in the field of synthetic organic chemistry. Preferably thealkylating agent is an organometallic compound, especially anorganoaluminium compound (such as trimethylaluminium (TMA), dimethylaluminium chloride, triethylaluminium) or a compound such as methyllithium, dimethyl magnesium, triethylboron, etc.

[0095] The quantity of alkylating agent used will depend upon the numberof active sites on the surface of the carrier. Thus for example, for asilica support, surface hydroxyls are capable of reacting with thealkylating agent. In general, an excess of alkylating agent ispreferably used with any unreacted alkylating agent subsequently beingwashed away.

[0096] Where an organoaluminium alkylating agent is used, this ispreferably used in a quantity sufficient to provide a loading of atleast 0.1 mmol Al/g carrier, especially at least 0.5 mmol Al/g, moreespecially at least 0.7 mmol Al/g, more preferably at least 1.4 mmolAl/g carrier, and still more preferably 2 to 3 mmol Al/g carrier. Wherethe surface area of the carrier is particularly high, lower aluminiumloadings may be used. Thus for example particularly preferred aluminiumloadings with a surface area of 300-400 m²/g carrier may range from 0.5to 3 mmol Al/g carrier while at surface areas of 700-800 m²/g carrierthe particularly preferred range will be lower.

[0097] Following treatment of the support material with the alkylatingagent, the support is preferably removed from the treatment fluid andany excess treatment fluid is allowed to drain off.

[0098] The optionally alkylated support material is loaded with theprocatalyst, preferably using a solution of the procatalyst in anorganic solvent therefor, e.g. as described in the patent publicationsreferred to above. Preferably, the volume of procatalyst solution usedis from 50 to 500% or the pore volume of the carrier, more especiallypreferably 80 to 120%. The concentration of procatalyst compound in thesolution used can vary from dilute to saturated depending on the amountof metallocene active sites that it is desired be loaded into thecarrier pores.

[0099] The active metal (ie. the metal or the procatalyst) is preferablyloaded onto the support material at from 0.1 to 4%, preferably 0.5 to3.0%, especially 1.0 to 2.0%, by weight metal relative to the dry weightof the support material.

[0100] After loading of the procatalyst onto the support material, theloaded support may be recovered for use in olefin polymerization, e.g.by separation of any excess procatalyst solution and if desired dryingor the loaded support, optionally at elevated temperatures, e.g. 25 to80° C.

[0101] Alternatively, a cocatalyst, e.g. an alumoxane or an ioniccatalyst activator (such as a boron or aluminium compound, especially afluoroborate) may also be mixed with or loaded onto the catalyst supportmaterial. This may be done subsequently or more preferablysimultaneously to loading of the procatalyst, for example by includingthe cocatalyst in the solution of the procatalyst or, by contacting theprocatalyst loaded support material with a solution of the cocatalyst orcatalyst activator, e.g. a solution in an organic solvent. Alternativelyhowever any such further material may be added to the procatalyst loadedsupport material in the polymerization reactor or shortly before dosingof the catalyst material into the reactor.

[0102] In this regard, as an alternative to an alumoxane it may bepreferred to use a fluoroborate catalyst activator, especially aB(C₆F₅)₃ or more especially a ⊖B(C₆F₅)₄ compound, such asC₆H₅N(CH₃)₂H:B(C₆F₅)₄ or (C₆H₅)₃C:B(C₆F₅)₄. Other borates or generalformula (cation⁺)_(a) (borate⁻)_(b) where a and b are positive numbers,may also be used.

[0103] Where such a cocatalyst or catalyst activator is used, it ispreferably used in a mole ratio to the metallocene of from 0.1:1 to10000:1, especially 1:1 to 50:1, particularly 1:2 to 30:1. Moreparticularly, where an alumoxane cocatalyst is used, then for anunsupported catalyst the aluminium:metallocene metal (M) molar ratio isconveniently 2:1 to 10000:1, preferably 50:1 to 1000:1. Where thecatalyst is supported the Al:M molar ratio is conveniently 2:1 to10000:1 preferably 50:1 to 400:1. Where a borane cocatalyst (catalystactivator) is used, the B:M molar ratio is conveniently 2:1 to 1:2,preferably 9:10 to 10:9, especially 1:1. When a neutral triarylborontype cocatalyst is used the B:M molar ratio is typically 1:2 to 500:1,however some aluminium alkyl would normally also be used. When usingionic tetraaryl borate compounds, it is preferred to use carboniumrather than ammonium counterions or to use B:M molar ratio below 1:1.

[0104] Where the further material is loaded onto the procatalyst loadedsupport material, the support may be recovered and if desired driedbefore use in olefin polymerization.

[0105] The olefin polymerized in the method or the invention ispreferably ethylene or an alpha-olefin or a mixture or ethylene and anα-olefin or a mixture of alpha olefins, for example C₂₋₂₀ olefins, e.g.ethylene, propene, n-but-l-ene, n-hex-l-ene, 4-methyl-pent-l-ene,n-oct-l-ene- etc. The olefins polymerized in the method of the inventionmay include any compound which includes unsaturated polymerizablegroups. Thus for example unsaturated compounds, such as C₆₋₂₀ olefins(including cyclic and polycyclic olefins (e.g. norbornene)), andpolyenes, especially C₆₋₂₀ dienes, may be included in a comonomermixture with lower olefins, e.g. C₂₋₅ α-olefins. Diolefins (ie. dienes)are suitably used for introducing long chain branching into theresultant polymer. Examples of such dienes include α,ω linear dienessuch as 1,5-hexadiene, 1,6-heptadiene, 1,8-nonadiene, 1,9-decadiene,etc.

[0106] In general, where the polymer being produced is a homopolymer itwill preferably be polyethylene or polypropylene. Where the polymerbeing produced is a copolymer it will likewise preferably be an ethyleneor propylene copolymer with ethylene or propylene making up the majorproportion (by number and more preferably by weight) or the monomerresidues. Comonomers, such as C₄₋₆ alkenes, will generally beincorporated to contribute to the mechanical strength or the polymerproduct.

[0107] Usually metallocene catalysts yield relatively narrow molecularweight distribution polymers; however, if desired, the nature or themonomer/monomer mixture and the polymerization conditions may be changedduring the polymerization process so as to produce a broad bimodal ormultimodal molecular weight distribution (MWD) in the final polymerproduct. In such a broad MWD product, the higher molecular weightcomponent contributes to the strength or the end product while the lowermolecular weight component contributes to the processability of theproduct, e.g. enabling the product to be used in extrusion and blowmoulding processes, for example for the preparation of tubes, pipes,containers, etc.

[0108] A multimodal MWD can be produced using a catalyst material withtwo or more different types of active polymerization sites, e.g. withone such site provided by the metallocene on the support and furthersites being provided by further catalysts, e.g. Ziegler catalysts, othermetallocenes, etc. included in the catalyst material.

[0109] Polymerization in the method of the invention may be effected inone or more, e.g. 1, 2 or 3, polymerization reactors, using conventionalpolymerization techniques, e.g. gas phase, solution phase, slurry orbulk polymerization.

[0110] In general, a combination of slurry (or bulk) and at least onegas phase reactor is often preferred, particularly with the reactororder being slurry (or bulk) then one or more gas phase.

[0111] For slurry reactors, the reaction temperature will generally bein the range 60 to 110° C. (e.g. 85-110° C.), the reactor pressure willgenerally be in the range 5 to 80 bar (e.g. 50-65 bar), and theresidence time will generally be in the range 0.3 to 5 hours (e.g. 0.5to 2 hours). The diluent used will generally be an aliphatic hydrocarbonhaving a boiling point in the range −70 to +100° C. In such reactors,polymerization may if desired be effected under supercriticalconditions.

[0112] For gas phase reactors, the reaction temperature used willgenerally be in the range 60 to 115° C. (e.g. 70 to 110° C.), thereactor pressure will generally be in the range 10 to 25 bar, and theresidence time will generally be 1 to 8 hours. The gas used willcommonly be a non-reactive gas such as nitrogen together withmonomer(e.g. ethylene).

[0113] For solution phase reactors, the reaction temperature used willgenerally be in the range 130 to 270° C., the reactor pressure willgenerally be in the range 20 to 400 bar and the residence time willgenerally be in the range 0.1 to 1 hour. The solvent used will commonlybe a hydrocarbon with a boiling point in the range 80-20020 C.

[0114] Generally the quantity of catalyst used will depend upon thenature or the catalyst, the reactor types and conditions and theproperties desired for the polymer product. Conventional catalystquantities, such as described in the publications referred to herein,may be used.

[0115] All publications referred to herein are hereby incorporated byreference.

EXPERIMENTAL

[0116] General Considerations

[0117] All operations were carried out in argon or nitrogen atmosphereusing standard Schlenk, vacuum and dry box techniques. Solvents weredried with potassium benzophenone ketyl and distilled under argon priorto use. 1.5.7-triaza[4.4.0]bicyclo-dec-5-ene (TAB-H) (Fluka) anddipyridylketone (DPM-H) (Fluka) were used as purchased. Benzyl potassiumwas prepared according to Schlosser, M. and Hartmann, J. Angew. Chem1973, 85, 544-545. CrCl₃(THF)₃ and TiCl₃(THF)₃ were prepared accordingto W. A. Herrmann and G. Brauer, Synthetic Methods or Organometallic andInorganic Chemistry, Vol. 1: Literature, Laboratory Techniques andCommon Starting Materials, Thieme 1996. 1H- and 13C-NMR spectra wererecorded using JEOL JNM-EX 270 MHz FT NMR spectrometer withtetramethylsilane (TMS) as an internal reference. 13C-CPMAS NMR and themass spectra were recorded at Fortum Oil and Gas Oy, Analytical Researchdepartment. The CPMAS-NMR spectra were recorded using ChemagneticsInfinity 270 MHz equipment and the direct inlet MS spectra were producedby VG TRIO 2 quadrupole mass spectrometer in electron impact ionisationmode (EIMS) (70 eV). The GC-MS analyses were performed using HewlettPackard 6890/5973 Mass Selective Detector in electron impact ionisationmode (70 eV) equipped with a silica capillary column (30 m×0.25 mmi.d.). The FTIR spectra were recorded at Borealis Analytical Researchdepartment using Perkin-Elmer Spectrum 2000 spectrometer with inertdiamond ATR accessory and 4 cm-1 resolution. Thermogravic measurements(TG) were recorded using GWB METTLER TG50 Termobalance and theDifferential Scanning Calorimetry (DSC) and melting point analyses usingGWB METTLER DSC-30 under inert conditions at Borealis AnalyticalResearch department. The polymerization tests were carried out usingMAO, 30% solution in toluene purhased from Albermarle. Testpolymerizations were carried out in pentane at 60° C. and at 80° C. withhydrogen present using an Al/M ratio or 1000 unless otherwise stated. ABüchi 2 L stirred reactor with mantle heating was used for thepolymerization tests.

EXAMPLE 1

[0118] Synthesis of (1.5.7-triaz[4.4.0]bicyclo-dec-5-enyl) potassium,C₇H₁₂KN₃

[0119] Red solid benzyl potassium (9.6 g, 73.3 mmol) was added into thesolution of 1.5.7-triaza[4.4.0]bicyclo-dec-5-ene (10.2 g, 73.3 mmol) in350 ml of dry toluene at −40° C. The temperature was allowed to warm toroom temperature and the mixture stirred for 16 hours. The colourchanged via red to a white slurry. The solvents were removed in avacuum, the product washed with 3×60 ml of ether and dried in a vacuumto obtain 10.1 g (78%) of white powder. ¹H-NMR in THF-d₈; δ: 3.17 (t,4H); 2.98 (t, 4H); 1.69 (t, 4H). The potassium salt product could not beanalysed with MS. Elemental analysis calc.: C 47.4%, H 6.8%, N 23.7%, K22.1%. Elemental analysis found: C 46.0%, H 6.4%, N 23.1%.

EXAMPLE 2

[0120] Synthesis of triazabicyclodec-ene-yl-1-dimethylsilylchlorideC₉H₁₈ClN₃Si.

[0121] 1.5.7-triaza[4.4.0]bicyclo-dec-5-enyl potassium 13.0 g (73.1mmol) dissolved in 200 mL of THF was added into a solution of 55 mL(438.6 mmol) of Me₂SiCl₂ in 50 mL THF over 3 hours at ambienttemperature. Colour changed from yellow to dark yellow. The solution wasstirred for 2 hours at ambient temperature after which the mixturecontaining a gelish precipitate of KCl was filtrated and washed with2×30 mL of THF. Solvent was removed under vacuum to obtain an off yellowsolid which was extracted with 3×30 mL of pentane and and filtrated. Theproduct was purified by recrystallization and filtration from cold (−30°C.) pentane yielding colorless, needle-like crystals. Yield 12.9 g(76.4%). ¹H-NMR CDCl₃ δ: 3.16 (t, 4H), 3.11 (t, 4H), 1.88 (t, 4H), 0.46(s, 6H). ¹³C-NMR CDCl₃δ: 154.9, 45.3, 38.6, 23.3, 7.9. EIMS analysisshowed the decomposition pattern of the parent ion of the title compoundC₉H₁₈ClN₃Si M⁺=231.80 g mol⁻¹. Elemental analysis calc. C 46.63%, H7.83%, N 18.13%, Cl 15.29%, Si 12.12%; Found. C 46.52%, H 7.80%, N18.24%, Cl 15.15%, Si 12.05%.

EXAMPLE 3

[0122] t-Butyldimethylsiloxy-3,4-dimethylcyclopentadienyl lithium

[0123] 40.0 g (465 mmol) orcrotonic acid (Fluka 28010), 25.1 g (418mmol) of isopropanol (Merck 1.09634.2500), 200 mL of benzene, 4.2 g ofconc. H₂SO₄ and 2.1 g of para-toluene sulfonic acid was charged to a 500mL flask equipped with a magnetic stirrer bar and Dean-Stark waterseparator. The mixture was refluxed until water formation ceased. 200 mLof ether was added to the mixture, and then washed with several portionsof NaHCO₃ (aq., sat.) until the the acid was neutralized. Organic phasewas separated, dried with MgSO₄ and filtered. Solvent was removed underreduced pressure and the remainder distilled at 95° C. to give 30.5 g ofisopropylcrotonate. Yield 57%. ¹H-NMR (CDCl₃): 6.95 (dq, 1H), 5.82 (d,1H), 5.05 (sept, 1H), 1.88 (d, 3H), 1.25 (d, 6H).

[0124] 811 g of polyphosphoric acid (Fluka 81340) was loaded to a roundbottom flask equipped with a reflux condenser and a magnetic stirrer barand heated to 100° C. 104 g (810 mmol) of isopropylcrotonate was addedto the flask and the mixture was stirred for2 hours at 100° C. Theresulted mixture was poured to >>1,5 kg of crushed ice. At roomtemperature the mixture was saturated with NH₄Cl and extracted with4×100 mL of ether. The combined ether fractions were dried over MgSO₄and filtered. Solvent was removed under reduced pressure and theremainder distilled (0.2 mbar, 33° C., bath 90° C.) to give 47.99 g of3,4-dimethylcyclopentenone. Yield 54%. ¹H-NMR (CDCl₃): 5.86 (s, 1H),2.80 (m, 1H), 2.64 (dd, 1H), 2.07 (s, 3H), 2.00 (dd, 1H), 1.18 (d, 3H).

[0125] 12.23 g (111.0 mmol) of 3,4-dimethylcyclopentenone, 11.31 g(111.8 mmol) of triethylamine dried with molecular sieves and 300 mL ofdry pentane were mixed at room temperature. During 13 minutes 29.44 g(111.4 mmol) of t-butyldimethylsilyltrifluoromethylsulfonate (Fluka97742) was added to the mixture. After strirring for 2.5 hour thesupernatant pentane fraction was separated, solvent removed underreduced pressure and the remainder distilled (0.03 mbar, 34-40° C., bath100° C.) resulting in 19.74 g of isomer isomer mixture oft-butyldimethylsiloxy-3,4-dimethylcyclopentadienes. Yield 79%. 1H-NMRspectrum was complicated due to presence of at least 3 isomers. Theproduct was characterised by GC/MS technique, which showed presence ofthree components (GC) each showing M+ peak at 224 (MS).

[0126] 10 g (44.6 mmol) of isomer mixture oft-butyldimethyl-siloxy-3,4-dimethylcyclopentadienes was mixed with 200mL of pentane at room temperature. At −20° C. 28.4 mL (44.6 mmol) of1.57 M t-butyllithium solution in hexanes (Acros 18128-0900) was added.Temperature was increased to 20° C. during 15 hours while stirring. Theresulted solid product was separated by filtration and washed with 2×100mL of pentane. Remaining solvent was removed under reduced pressure.7.07 g of t-butyl-dimethylsiloxy-3,4-dimethylcyclopentadienyl lithiumwas isolated. Yield 69%. ¹H-NMR (THF-d₈): 4.88 (s, 2H), 1.95 (s, 6H),0.95 (s, 9H), 0.08 (s, 6H).

EXAMPLE 4

[0127] Synthesis of Tri-isopropylsiloxycyclopentadienyl lithium

[0128] Triisopropylsiloxycyclopentadiene was prepared analogously toexample 3 using triisopropylsilyl-trifluoromethylsulfonate (Fluka 91746)and cyclopent-2-enone (Fluka 29827) as starting materials. It was notisolated but lithiated immediately to avoid spontaneous Diels-Alderdimerisation of the product. Lithiation was performed analogously toexample 3 and afforded triisopropylsiloxycyclopentadienyl lithium in 81%yield. ¹H-NMR (THF-d₈): 5.22 (m, 2H), 5.17 (m, 2H), 1.11 (m, 3H), 1.04(d, 18H).

EXAMPLE 5

[0129] Synthesis oftriazabicyclodec-ene-yl-1-dimethylsilyl-dimethyl-tertbutylsiloxydimethylcyclopentadiene (mixture of isomers) C₂₂H₄₁N₃OSi₂

[0130] 1.2 g (5.21 mmol) oft-butyldimethylsiloxy-3,4-dimethylcyclopentadienyl lithium dissolved in100 mL of THF was added over 1 h into a solution of 1.2 g (5.21 mmol) oftriazabicyclodec-ene-yl-1-dimethylsilylchloride in 50 mL of THF at −70°C. to give an orange transparent solution. The solution was refluxed for16 hours after which the solvent was removed under vacuum. The productwas extracted into pentane, filtrated and cooled to −30° C. for 16hours. Trace insolubilities were filtrated off at −30° C. and thesolvent removed under vacuum to give 98% pure, brown oily mixture ofdouble bond and stereoisomers. Yield 1.6 g (73.3%). The EIMS analysisshowed the decomposition pattern of the parent ion of the title compoundC₂₂H₄₁N₃OSi₂ M⁺=419.76 g mol⁻¹, fragmentation peaks at 404, 270, 224 and196. ¹H-NMR of the major isomer in THF-d₈ δ: 5.02 (s, 1H) 3.41 (s, 1H)3.18 (m, 4H) 3.06 (m, 4H) 2.02 (s, 3H) 1.95 (s, 3H) 1.78 (m, 4H) 0.97(s, 9H) 0.24 (s, 3H), 0.22 (s, 3H), 0.19 (s, 3H), 0.10 (s, 3H). ¹³C-NMRTHF-d₈ δ: 160.9, 151.6, 131.7, 124.6, 110.6, 95.5, 53.0, 48.9, 43.3,27.0, 26.4, 24.7, 13.0, 0.9, −4.1, −4.6.

EXAMPLE 6

[0131] Synthesis oftriazabicyclodec-ene-yl-1-dimethylsilyl-dimethyl-tertbutylsiloxydimethylcyclopentadienyl chromium dichloride C₂₂H₄₀Cl₂CrN₃OSi₂

[0132] 1.8 mL of MeLi (1.6 M solution in diethyl ether, 3.34 mmol) wasadded into a solution of 1.6 g (3.34 mmol) oftriazabicyclodec-ene-yl-1-dimethylsilyl-dimethyl-tertbutylsiloxydimethylcyclopentadiene in 50 mL THF at +50° C. over 5 minutes andstirred at ambient temperature for 16 hours. CrCl₃(THF)₃ (3.34 mmol)dissolved in THF was added over 40 minutes at −50° C. to give a darkblue solution which was stirred at ambient temperature for 16 hours.Solvents were removed under vacuum and the product extracted in toluene,filtered and evaporated. The raw product was purified by washing withcold pentane. Yield 1.0 g (52.2%) of dark blue microcrystalline solid.The compound was paramagnetic, NMR identification was not possible. TheEIMS analysis showed the decomposition pattern of the parent ion of thetitle compound C₂₂H₄₀Cl₂CrN₃OSi₂ M⁺=541.65 g mol⁻¹, fragmentation peaksat 504, 468, 418, 287, 224, 196 and 138. Melting point: 145° C. (broadpeak in DSC). TG analysis (from 30° C. to 891° C., 10° C./min) showed57.7% loss of weight in a one phase process at 286° C. averaged deltatemperature. Crystals suitable for X-ray analysis were not obtainedbecause of the presence of the two stereoisomers (rac and meso type)which resulted in the precipitation of microcrystalline solid. Elementalanalysis calc. C 48.78%, H 7.44%, N 7.76%, Cl 13.09%, Si 10.37%, Cr9.60%; Found C 49.02%, H 7.56%, N 7.94%, Cl 12.91%, Si 10.11%, Cr 9.44%.

EXAMPLE 7

[0133] Synthesis oftriazabicyclodec-ene-yl-1-dimethylsilyl-tri-isopropylsiloxycyclopentadiene (Mixture Orisomers) C₂₃H₄₃N₃OSi₂

[0134] 3.2 g (12.3 mmol, 92.6%) of tri-isopropylsiloxy-cyclopentadienyllithium dissolved in 70 mL of THF was added over 40 minutes into asolution of 2.8 g (12.3 mmol) oftriazabicyclodec-ene-yl-1-dimethylsilylchloride in 70 mL of THF at −70°C. to give a red mixture. The mixture was refluxed for 16 hours afterwhich the solvent was removed under vacuum. The product was extractedinto pentane, filtrated and the filtrate cooled to −30° C. for 16 hoursafter which the insolubles were filtered off at −30° C. The filtrate wasthen cooled to −70° C. for 6 h and the trace insolubles filtrated off at−70° C. The pentane was then removed under vacuum to give a dark brown,viscous oily mixture of double bond and regioisomers. Yield 3.1 g(57.6%). The EIMS analysis showed the decomposition pattern of theparent ion of the title compound C₂₃H₄₃N₃OSi₂ M⁺=433.78 g mol⁻¹,fragmentation peaks at 418, 390, 238 and 196. ¹H-NMR major isomer inTHF-d₈ δ: 6.39 (m, 1H) 6.21 (m, 1H) 5.62 (m, 1H) 3.19 (m, 4H) 3.08 (m,4H) 2.92 (m, 1H) 1.80 (m, 4H) 1.20 (m, 3H) 1.18 (s, 18H) 0.25 (s, 6H).¹³C-NMR major isomer (1,3-substituted regioisomer) in THF-d₈ δ: 149.0,131.8, 130.8, 130.0, 105.0, 102.0, 47.0, 41.2, 22.7, 16.2, 11.2, 0.4.The compound decomposed during the elemental analysis samplepreparation.

EXAMPLE 8

[0135] Synthesis oftriazabicyclodec-ene-yl-1-dimethylsilyl-tri-isopropylsiloxycyclopentadienyl chromium dichloride (Mixture of Isomers)C₂₃H₄₂N₃Cl₂CrOSi₂

[0136] 3.7 mL of MeLi (1.9 M solution in diethyl ether, 7.04 mmol) wasadded into a solution of 3.1 g (7.04 mmol) oftriazabicyclodec-ene-yl-1-dimethylsilyl-tri-isopropylsiloxy-cyclopentadienein 70 mL THF at +50° C. over 5 minutes and stirred at ambienttemperature for 16 hours. CrCl₃(THF)₃ (7.04 mmol) dissolved in 50 mL THFwas added over 30 minutes at −30° C. to give a dark blue-green solutionwhich was stirred at ambient temperature for 16 hours. Solvents wereremoved under vacuum and the product extracted in toluene, filtered andevaporated. The raw product was purified by washing with cold pentane.Yield 1.9 g (48.6%) of blue-green microcrystalline solid. The compoundwas paramagnetic, NMR identification was not possible. The EIMS analysisshowed the decomposition pattern of the parent ion of the title compoundC₂₃H₄₂Cl₂CrN₃OSi₂ M⁺=555.68 g mold⁻¹, fragmentation peaks at 499, 477,238, 192 and 178. Melting point: 170.9° C. (broad peak in DSC). TGanalysis (from 30° C. to 891° C., 10° C./min) showed 55.2% loss ofweight in a two phase process at 242° C. averaged delta temperature. Mp170.9° C. Crystals suitable for X-ray analysis were not obtained becauseof the presence or the two stereoisomers (rac and meso type) whichresulted in the precipitation of microcrystalline solid. Elementalanalysis calc. C 49.71%, H 7.62%, N 7.56%, Cl 12.76%, Cr 9.36%, O 2.88%,Si 10.11%; Found C 49.50%, H 7.65%, N 7.31%, Cl 12.93%, Si 9.98%, Cr9.48%.

EXAMPLE 9

[0137] Synthesis ortriazabicyclodec-ene-yl-1-dimethylsilyl-fluoreneC₂₂H₂₇N₃Si

[0138] Fluorenyllithium (prepared from fluorene via treatment ofbutyllithium) 0.7 g (4.08 mmol) dissolved in 50 mL of THF was added over30 minutes into a solution of 0.9 g (4.08 mmol) oftriazabicyclodec-ene-yl-1-dimethyl-silylchloride in 50 mL of THF at −70°C. The yellowish solution was stirred at ambient temperature for 16hours after which the solvent was removed under vacuum. The product wasextracted into pentane, filtrated and cooled to −30° C. for 16 hours.The product precipitated as yellowish transparent crystals which werefiltrated and dried in a vacuum. Yield 1.1 g (73.8%). The EIMS analysisshowed the decomposition pattern of the parent ion of the title compoundC₂₂H₄₁N₃OSi₂ M⁺=361.56 g mol⁻¹, fragmentation peaks at 346, 196, 165 and138. ¹H-NMR in CDCl₃ δ: 7.90 (d, 2H), 7.58 (d, 2H), 7.38 (dd 2H) 7.30(dd, 2H), 4.95 (s, 1H) 3.22 (t, 4H) 3.19 (t, 4H) 1.91 (q, 4H) −0.1 (s,6H). ¹³C-NMR in CDCl₃ δ: 161.3, 146.3, 140.7, 125.7, 124.7, 124.3,119.5, 48.3, 43.2, 42.7, 23.8, −2.5.

EXAMPLE 10

[0139] Synthesis of triazabicyclodec-ene-yl-1-dimethylsilyl-fluorenylchromium dichloride C₂₂H₂₆Cl₂CrN₃Si (Descriptive Example)

[0140] 1.7 mL of methyl lithium (2.94 mmol, 1.76 M solution in diethylether) was added at −30° C. into a solution oftriazabicyclodec-ene-yl-1-dimethylsilyl-fluorene 1.1 g (2.94 mmol) in 50mL of THF. The solution became bright neon yellow and yellowishprecipitate formed. The mixture was stirred at ambient temperature for16 hours. Then CrCl₃(THF)₃ (2.94 mmol) dissolved in 50 mL THF was addedinto the solution at −30° C. and the mixture stirred at ambienttemparature for 16 hours. Solvents were removed under a vacuum and theproduct extracted in toluene, filtered and evaporated. The paramagneticproduct was purified by washing with cold pentane and evaporated.

EXAMPLE 11

[0141] Synthesis of triazabicyclodec-ene-yl-1-diphenylsilylchlorideC₁₉H₂₂ClN₃Si

[0142] 1.5.7-Triaza[4.4.0]bicyclo-dec-5-enyl potassium 3.0 g (16.9 mmol)dissolved in 50 mL of THF was added into a solution of 21 mL (101.5mmol) of Ph₂SiCl₂ in 50 mL THF over 3 hours at ambient temperature.Colour changed from whitish to light yellow. The solution was stirredfor 2 hours at ambient temperature after which the mixture containing agelish precipitate of KCl was filtrated and washed with 2×30 mL of THF.Solvents were removed under vacuum to obtain a slightly viscous liquid.Then 50 mL of pentane was added to the filtrate and the precipitatedproduct separated by filtration and washed with 2×30 mL of more pentane.Yield 5.2 g (87.3%) of white solid. ¹H-NMR CDCl₃ δ: 7.52 (dd, 4H), 7.34(d, 2H), 7.32 (d, 4H), 3.25 (m, 4H), 3.15 (t, 4H), 1.96 (q, 4H). ¹³C-NMRCDCl₃ δ: 155.1, 141.0, 134.0, 128.3, 127.2, 46.6, 38.8, 23.2. The EIMSanalysis showed the decomposition pattern of the parent ion of the titlecompound C₁₉H₂₂ClN₃Si M⁺=355.94 g mol⁻¹, frgamentation peaks at 320, 278and 138. Elemental analysis calc. C 64.11%, H 6.23%, N 11.81%, Cl 9.96%,Si 7.89%; Found C 63.89%, H 6.20%, N 11.97%, Cl 9.90%, Si 7.74%.

EXAMPLE 12

[0143] Synthesis oftriazabicyclodec-ene-yl-1-diphenylsilyl-tetramethylcyclopentadieneC₂₈H₃₅N₃Si

[0144] Tetramethylcyclopentadienyl lithium 1.04 g (8.15 mmol) (preparedfrom tetramethylcyclopentadiene via treatment of n-butyllithium)dissolved in 50 mL THF was added into a solution oftriazabicyclodec-ene-yl-1-diphenyl-silylchloride in 50 mL of THF over 20minutes at −30° C. The mixture was stirred at ambient temperature for 16hours, after which the solvents were removed under vacuum, the productextracted in pentane, filtered and evaporated. Yield 2.2 g (61.1%) ofwhite solid. The EIMS analysis shows the decomposition pattern of theparent of the title compound C₂₈H₃₅N₃Si M⁺441.69 g mol⁻¹. ¹H-NMR THF-d₈δ: 7.54 (d, 4H), 7.22 (m, 4H), 7.20 (d, 4H), 4.21 (s, 1H), 3.17 (t, 4H),3.03 (t, 4H), 1.83 (s, 6H), 1.75 (m, 4H), 1.42 (s, 6H). ¹³C-NMR THF-d₈δ: 151.9, 136.8, 136.7, 136.6, 133.3, 128.9, 126.9, 54.8, 48.6, 43.4,24.7, 14.5, 11.6. Elemental analysis calc. C 76.14%, H 7.99%, N 9.51%,Si 6.36%; Found C 76.04%, H 8.13%, N 9.54%, Si 6.38%.

EXAMPLE 13

[0145] Synthesis oftriazabicyclodec-ene-yl-1-diphenylsilyl-tetramethylcyclopentadienylchromium dichloride C₂₈H₃₄Cl₂CrN₃Si

[0146] 4.6 mL of methyl lithium (8.15 mmol, 1.76 M solution in diethylether) was added into a solution oftriazabicyclodec-ene-yl-1-diphenylsilyl-tetramethylcyclopentadiene in 50mL of THF at −30° C. The solution was stirred at ambient temperature for16 hours. A whitish precipitate formed. Then CrCl₃(THF)₃ dissolved in 50mL of THF (8.15 mmol) was added over 30 minutes at −30° C., and themixture stirred 16 hours at ambient temperature. The solvent was removedunder vacuum and the product extracted in toluene, filtered andevaporated. EIMS M®=563.59 g mol⁻¹. Elemental analysis calc. C 59.67%, H6.08%, N 7.46%, Cl 12.58%, Si 4.98%, Cr 9.23%; Found C 59.42%, H 6.23%,N 7.52%, Cl 12.82%, Si 5.05%, Cr 9.35%.

EXAMPLE 14

[0147] Synthesis of trimethylsiloxycyclopentadiene

[0148] 9.1 g (111.0 mmol) of cyclopent-2-en-1-one (Fluka 29827), 11.31 g(111.8 mmol) of triethylamine dried with molecular sieves and 300 mL ofdry pentane are mixed at room temperature. Over 13 minutes 24.75 g(111.4 mmol) of trimethylsilyl-trifluoromethylsulfonate (Fluka 91741) isadded to the mixture. After strirring for 2.5 hour the supernatantpentane fraction is separated, solvent removed under reduced pressureand the remainder distilled under reduced pressure resulting in anisomer mixture of trimethylsiloxycyclopentadienes. The product ischaracterised by ¹H-NMR and GC/MS⁺.

[0149] Trimethylsiloxycyclopentadienyl lithium is prepared as describedin the last section of example 3 by using t-BuLi.

[0150] Trimethylsiloxycyclopentadiene can also be synthesised accordingto the description in Acta. Chem. Scandinavica, 43, 1989, 188-92 (Scheme2). 1.74 g of LiBr (20 mmol, dried under vacuum at 400° C.) is dissolvedin 5.55 g of THF (77 mmol). At −15° C., 1.54 g of chlorotrimethylsilane(15 mmol), 1.23 g of cyclopent-2-en-1-one (15 mmol) and 1.51 g oftriethylamine (15 mmol, dry) are added to the solution. After 1 hour at−15° C. and 24 hours at +40° C. the crude product is isolated by lowtemperature aquous NaCl/NaHCO₃ and pentane extractions. The crudetrimethylsiloxycyclopentadienes are purified by distillation underreduced pressure. Trimethylsiloxycyclopentadienyl lithium is prepared asdescribed in the last section of example 3 by using t-BuLi.

EXAMPLE 15

[0151] Synthesis oftriazabicyclodec-ene-yl-1-diphenylsilyl-trimethylsiloxycyclopentadieneC₂₇H₃₅N₃OSi₂

[0152] Trimethylsiloxycyclopentadienyl lithium (8.15 mmol) (preparedfrom trimethylsiloxycyclopentadiene via treatment of t-butyllithium)dissolved in 50 mL THF is added into a solution oftriazabicyclodec-ene-yl-1-diphenylsilylchloride in 50 mL of THF over 20minutes at −30° C. The mixture is stirred at ambient temperature for 16hours, after which the solvents are removed under vacuum, the productextracted in pentane, filtered and the major kinetically formed isomerwith 1,3-substitution pattern of the siloxy and the bridge subtituentson the Cp ring is obtained via recrystallization from cold pentane.

EXAMPLE 16

[0153] Synthesis oftriazabicyclodec-ene-yl-1-diphenylsilyl-trimethylsiloxycyclopentadienylchromium dichloride C₂₇H₃₄Cl₂CrN₃OSi₂

[0154] Methyl lithium (8.15 mmol, 1.76 M solution in diethyl ether) isadded into a solution oftriazabicyclodec-ene-yl-1-diphenylsilyl-tetramethylcyclopentadiene in 50mL of THF at −30° C. The solution is stirred at ambient temperature for16 hours. A whitish precipitate forms. Then CrCl₃(THF)₃ dissolved in 50mL of THF (8.15 mmol) is added over 30 minutes at −30° C., and themixture stirred 16 hours at ambient temperature. The solvent is removedunder vacuum and the product extracted in toluene, filtered andevaporated to give a blue solid product.

EXAMPLE 17

[0155] Synthesis of dipyridin-2-ylmethane C₁₁H₁₀N₂

[0156] Solid KOH (9.4 g, 167.7 mmol) was dissolved in 15 mL of distilledwater and poured into an autoclave reactor (Parr pressure reactor) undernitrogen atmosphere. Di(2-pyridyl) ketone (15.0 g, 81.4 mmol) wasweighed and introduced into the reactor. Hydrazine monohydrate (6.1 mL,185.7 mmol) was poured into the reaction mixture and the reactor closed.The reactor was mounted on a Parr heater unit and the reaction mixturestirred for 18 h at 150° C. at 28 bar. After 1 hour the temperature was150° C. and the pressure 5 bar. After 18 h heating and stirring thetemperature was 151° C. and the pressure inside the reactor 28 bar.After the reaction was complete, the cooled reactor was opened at airatmosphere and the yellowish liquid obtained neutralized with 1M HCl(aq.) and extracted with 3×50 mL chloroform. Organic phase was washedwith 3×30 mL of brine and dried over MgSO₄. Solvents were removed in avacuum and the crude product distilled in a vacuum to obtain a yellowliquid with b.p. 80-85° C./0.06 m bar. Yield: 9.8 g (72%). ¹H-NMR inCDCl₃; δ: 8.48 (m, 2H); 7.51 (m, 2H); 7.19 (t, 2H); 7.04 (m, 2H); 4.29(s, 2H). EIMS analysis showed parent ion of the title compound C₁₁H₁₀N₂corresponding to molecular weight M⁺=170.21 g mol⁻¹.

EXAMPLE 18

[0157] Synthesis of dipyridin-methan-2-yl-potassium C₁₁H₉KN₂

[0158] Benzyl potassium 4.0 g (30.5 mmol) was added into a solution ofdipyridin-2-ylmethane 5.2 g (30.5 mmol) in 100 mL THF at −70° C. over 10minutes. The mixture was stirred at ambient temperature for 16 hoursafter which the bright yellow mixture was filtrated and washed with THF.Solvents were evaporated and the product washed with pentane andevaporated to yield a bright yellow solid which on the basis of the¹H-NMR spectrum in DMSO-d₆ was [DPM⁻K⁺] [THF]_(0.5). Yield 5.44 g(73.0%) based the THF complex (M_(w)=244.35 g mol−1). The productdecomposed during ETMS analysis. Elemental analysis calculated for[DPM^(−K) ^(+] [THF]) _(0.5): C 64.6%, H 4.8%, N 12.0%, K 21.9%. Found:C 63.9%, H 5.36%, N 11.46%, K 16.0%. NMR spectra were recorded at +22.7°C., +50° C. and at +70° C. in DMSO-d₆. The complex shows fluxionalbehaviour in NMR with increasing temperature which is caused by thetransition between the two resonance structures A and B. The peakscoalescence at +70° C. The singlet bridgehead proton is exchanged slowlywith the methyl deuterium of DMSO-d₆ which is seen as an appearingtriplet in ¹³C-NMR. ¹H-NMR in DMSO-d₆ at +70° C. δ: 8.20 and 6.25 (broadcoalesence peaks, 2H, from H_(a)

H_(a′)), 7.65 (d, 2H, from H_(d)

H_(d′)), 6.78 (broad, 2H, from H_(b)

H_(b′)), 5.76 (broad, 2H, from H_(c)

H_(c′)), 4.62 (S, 1H, exchangeable proton H_(e)). ¹³C-NMR in DMSO-d₆ atδ: 160.2, 147.9, 147.8, 132.3, 131.2, 116.9, 114,3, 105.3, 103.3,triplet 87.2 from exchanged CH_(e)

DMSO-d₆. ¹³C-CPMAS δ: 163, 150, 138, 119, 109, 82.

EXAMPLE 19

[0159] Synthesis oftriazabicyclodec-ene-yl-1-dimethylsilyl-dipyridin-methane C₂₀H₂₇N₅Si

[0160] Dipyridin-methan-2-yl-potassium 2.62 g (12.6 mmol) dissolved in100 mL THF of was added into a solution oftriazabicyclodec-ene-yl-1-dimethylsilylchloride 2.90 g (12.6 mmol) in100 mL of THF over 40 minutes at −70° C. The mixture was stirred atambient temperature for 16 hours. Solvent was evaporated under vacuum,the product extracted in toluene, filtrated and washed with moretoluene. Solvent was removed under vacuum and the product grinded inglove box. The product was purified by washing with cold pentane.Pentane solubles were filtered off and the product evaporated undervacuum. Yield 3.7 g (80.0%) of yellow solid. EIMS analysis showed thedecomposition pattern of parent ion of the title compound C₂₀H₂₇N₅Sicorresponding to molecular weight M⁺=365.55 g mol⁻¹, fragmentation peaksat 335, 258, 196, 169, 138. ¹H-NMR in THF-d₈ δ: 8.45 (d, 2H), 7.45 (dd,2H), 7.44 (d, 2H) 6.99 (t, 2H). 4.92 (s, 1H), 3.06 (t, 4H), 2.86 (t,4H), 1.61 (q, 4H), 0.16 (s, 6H). Elemental analysis calculated: C 65.7%,H 7.44%, N 19.2%. found: C 63.8%, H 6.8%, N 16.6%.

EXAMPLE 20

[0161] Synthesis of triazabicyclodec-ene-yl-1-dimethylsilyldipyridylmethan-yl chromium dichloride C₂₀H₂₈Cl₂CrN₅Si

[0162] 1.9 mL methyl lithium (3.7 mmol, 1.94 M solution in diethylether) was added into a solution oftriazabicyclodec-ene-yl-1-dimethylsilyl dipyridylmethane 1.33 g (3.6mmol) dissolved in 100 mL THF at −30° C. over 5 minutes. The mixture wasstirred at ambient temperature for 2 hours. CrCl₃(THF)₃ (3.6 mmol) wasadded at −30° C. over 30 minutes and the solution stirred at ambienttemperature over 16 hours. Solvents were removed under vacuum, theproduct extracted in toluene, filtered and evaporated. The product waspurified by washing with cold dichloromethane and pentane. Yield 0.2 g(25.5%) of dark brown tar. The product decomposed during EIMS analysis.The product was paramagnetic, NMR identification could not be obtained.

EXAMPLE 21

[0163] Synthesis of triazabicyclodec-ene-yl-1-dimethylsilyldipyridylmethan-yl chromium dichloride C₂₀H₂₈Cl₂TiN₅Si

[0164] 0.8 mL methyl lithium (1.64 mmol, 1.94 M solution in diethylether) was added into a solution oftriazabicyclodec-ene-yl-1-dimethylsilyl dipyridylmethane 0.60 g (1.64mmol) dissolved in 70 mL THF at −30° C. over 5 minutes. The mixture wasstirred at ambient temperature for 16 hours. TiCl₃(THF)₃ (1.64 mmol) wasadded at −70° C. over 20 minutes and the solution stirred at ambienttemperature over 3 hours. Solvents were removed under vacuum, theproduct extracted in toluene, filtered and evaporated. The product waspurified by washing with cold dichloromethane and pentane. Yield 0.5 g(64.9%) of dark brown tar. The product decomposed during EIMS analysis.The product was paramagnetic, NMR identification could not be obtained.

EXAMPLE 22

[0165] Dimethylmethylene cyclopentadienyl triazabicyclodec-ene-yl-1potassium C₁₅H₂₂KN₃

[0166] Dimethylfulvene 1.8 mL (14.7 mmol) was added to(1.5.7-triaza[4.4.0]bicyclo-dec-5-enyl) potassium 2.6 g (14.7 mmol) inTHF at 0° C. over one hour. The mixture was stirred at ambienttemperature overnight, and the solvent removed under vacuum. The productwas washed with pentane and dried under vacuum to afford 3.2 g (79.05%)or light grey solid. ¹H-NMR in THF δ: 5.92 (dd, 2H), 5.65 (dd, 2H), 3.10(t, 4H), 3.04 (t, 4H), 3.81 (s, 6H), 3.61 (m, 4H). ¹³C-NMR in THF δ:151.0, 142.4, 121.9, 105.8, 102.9, 48.2, 41.8, 23.6, 22.2. MS analysisshowed the decomposition pattern of the parent title compound. No M⁺ wasdetected due to the decomposition of the sample during the analysis.Elemental analysis calculated C 63.56% H 7.82% N 14.82% K 13.79%, foundC 63.36% H 7.75% N 15.07% K 13.55%.

EXAMPLE 23

[0167] Dimethylmethylene cyclopentadienyl triazabicyclodec-ene-yl-1chromium dichloride C₁₅H₂₂Cl₂CrN₃.

[0168] Dimethylmethylene cyclopentadienyltriazabicyclodec-ene-yl-1potassium CrCl₃(THF)₃ 3.4 g (9.08 mmol) in THFwas added to a solutiuon of triazabicyclodec-ene-yl-1-dimethyl-methylenepotassium 2.6 g (9.08 mmol) in THF at −30° C. over a period of 30minutes. The mixture was stirred overnight at ambient temperature.Solvent was removed under reduced pressure and the product extracted intoluene, filtrated and dried under vacuum. The filtrate was thenextracted in dichloromethane, filtrated, and dried again under vacuum.The product was washed with pentane to afford pure dark bluemicrocrystalline solid 2.3 g (68.7%). EIMS analysis showed thedecomposition pattern of the title compound, M⁺=367.26 g mol⁻¹ peak wasnot detected due to decomposition during analysis. Elemental analysiscalculated C 49.06% H 6.04% N 11.44% Cl 19.31% Cr 14.16%, found C 47.81%H 6.06% N 13.05% Cl 18.80% Cr 13.60%.

[0169] Polymerization Examples TABLE 1 Ethylene homopolymerization testresults using homogeneous catalysts Act. M_(w) × Cryst. m.p. ComplexHOPO 10³ M_(w)/M_(n) % ° C. Al/M Example 6 2778 n.d. n.d. 53.6 134.3 757Me₂Si(Me₂Cp—OSiMe₂—tBu)(TAB)CrCl₂ Example 8 395 977 30.2 57.1 135.1 778Me₂Si(Cp—OSi—iPr₃)(TAB)CrCl₂ Example 13 1048 412 27.8 66.7 133.2 1000Ph₂Si(Me₄Cp)(TAB)CrCl₂ Example 10 50 272 6.6 58.9 134.2 1000Me₂Si(Flu)(TAB)CrCl₂

[0170] TABLE 2 Ethylene homopolymerization using homogeneous catalystsand hydrogen Act. M_(w) × Cryst. m.p. Complex HOPO/H₂ 10³ M_(w)/M_(n) %° C. Al/M Example 6 1902¹   198 7.4 71.1 132.5 1000Me₂Si(Me₂Cp—OSiMe₂—tBu)(TAB)CrCl₂ Example 13 2628.1 — — — — —Ph₂Si(Me₄Cp)(TAB)CrCl₂ Example 8 486   192 8.1 67.3 135.7  763Me₂Si(Cp—OSi—iPr₃)(TAB)CrCl₂

[0171] TABLE 3 Copolymerization of ethylene and 1-hexene usinghomogeneous catalysts Act. Complex COPO Example 13 2713.5 Ph₂Si(Me₄Cp)(TAB) CrCl₂ Example 23 91.62 Me₂C(Cp) (TAB) CrCl₂

[0172] TABLE 4 Polymer double bond analysis results of the ethylenehomopolymers^(#) Complex t-vinylene vinyl vinylidene Example 6 0.11 0.090.03 Me₂Si (Me₂Cp—OSiMe₂—tBu) (TAB) CrCl₂ Example 8 n.d. n.d. n.d. Me₂Si(Cp—OSi—iPr₃) (TAB) CrCl₂ Example 13 0.21 0.71 0.12 Ph₂Si (Me₄Cp) (TAB)CrCl₂ Example 10 0   0.18 0.05 Me₂Si (Flu) (TAB) CrCl₂

[0173] TABLE 5 Propylene polymercisations. Al/Cr ratio 1000,polymerisation time 90 minutes. 5 bar propylene pressure (60° C.).Cocatalyst MAO & TIBA (tetraisobutylalumoxane) 150 μL, 1100 g propylene.Complex Yield of Polymer Notes Example 6 0.7 g Example 6 1.4 6 gEthylene added

[0174] TABLE 6 Analysis results of the polymers DSC, MN MW MW/ MZ T-Code Run Type DSC (%) TCR1 (° C.) TM1 (° C.) (g/mol) (g/mol) MN (g/mol)MFR21 VINYL VINYL VINYLIDEN 8 HOPO60 57.1 115.9 135.1 32300 977000 30.26302000 0.03 8 HOPO80 64 116.2 129.9 not done 0.16 1.46 0.6 8 HOPO/H26067.3 116.3 135.7 23600 192000 8.1 1392000 14.5 0 0.27 0.1 6 HOPO60 53.6115.9 134.3 0.008 0.11 0.09 0.0 6 HOPO80 72.3 118.2 131.3 28.4 0.84 0.680.2 6 HOPO/H260 71.1 119 132.5 26900 198000 7.4 3553000 42.5 0.06 0.090.0 Heterogeneous polymerisation test result of compound 20 using silicaActivity of cat Activity of metal Flowmeter DSC Pol type (KgPol/g cat h)KgPol/g met h) Al/Me C2 (g) Temperature (° C.) CR1 (%) TCR1 (° C.) TM1(° C.) HDPE 0.01 4.6 200 28 60 49.1 119.9 113.4 HDPE 0.00 4.3 200 24 8051.3 120 132.5 GPC-Normal MFR FTIR, (C = C/1000 C.) MN1 MW1 MW1/MN1 MZ121.6 KG T-VINYLENE VINYL VINYLIDENE 204600 1899000 9.3  6079000 not doneX X X 19000  1742000 91.7 9030000 not done X X X

1. A compound of formula (I)

wherein LIG represents an η⁵-ligand substituted by a group R₁ and agroup (R″)_(m); X represents a 1 to 3 atom bridge; Y represents anitrogen or phosphorus atom; Z represents a carbon, silicon, nitrogen orphosphorus atom; the ring denoted by A₁ is an optionally substituted,optionally saturated or unsaturated 5 to 12 membered heterocyclic ring;the ring denoted by A₂ is an optionally substituted, unsaturated 5 to 12membered heterocyclic ring; R₁ represents hydrogen, R″ or a groupOSiR′₃; each R′, which may be the same or different is a R⁺, OR⁺, SR⁺,NR⁺ ₂ or PR⁺ ₂ group where each R⁺ is a C₁₋₁₆ hydrocarbyl group, atri-C₁₋₈hydrocarbylsilyl group or a tri-C₁₋₈hydrocarbylsiloxy group;each R″, which may be the same or different is a ring substituent whichdoes not form a σ-bond to a metal η-bonded by the bicyclic ring; and mis zero or an integer between 1 and
 3. 2. A compound as claimed in claim1 wherein Z represents a nitrogen atom.
 3. A compound as claimed inclaim 1 or 2 wherein Y represents a nitrogen atom.
 4. A compound asclaimed in any one of claims 1 to 3 wherein A₁ and A₂ are five orsix-membered rings.
 5. A compound as claimed in any one or claims 1 to 4wherein A₁ and A₂ are unsubstituted and comprise only 1 double bond. 6.A compound as claimed in any one of claims 1 to 5 wherein A₁ and A₂represent


7. A compound as claimed in any one of claims 1 to 6 wherein LIGcomprises a dipyridymethanyl, cyclopentadienyl, fluorenyl or indenylligand.
 8. A compound as claimed in any one of claims 1 to 7 wherein R″represents hydrogen, R⁺, OR³⁰ , SR⁺, NR⁺ ₂ or PR⁺ ₂ group where eachR⁺is a C₁₋₁₆ hydrocarbyl group, a tri-C₁₋₈ hydrocarbylsilyl group or atri-C₁₋₈hydrocarbylsiloxy group.
 9. A compound as claimed in any one ofclaims 7 of 8 wherein LIG represents cyclopentadienyl and R₁ representsOSiR′₃ each R′ being a C₁₋₁₂ hydrocarbyl group.
 10. A compound asclaimed in claim 9 wherein R″ represents C₁₋₆ alkyl.
 11. A compound asclaimed in claim 1 wherein LIG represents


12. A compound as claimed in any one of claims 1 to 10 wherein m is 3,LIG is a cyclopentadienyl and R″ is methyl.
 13. A compound as claimed inany one of claims 1 to 12 wherein X is a one atom bridge comprising Sior a one atom bridge comprising a carbon atom.
 14. A compound as claimedin any one of claims 1 to 7 wherein LIG represents fluorenyl, indenyl ordipyridymethanyl and R′ and R″ represent hydrogen.
 15. A compound asclaimed in any one of claims 1 to 13 of formula

wherein R′, m and R″ are as hereinbefore defined.
 16. A procatalystcomprising a compound of formula (I) as claimed in any one of claims 1to 11 coordinated to a metal ion of group 3 to 7, the Y atom not beingcoordinated to the metal.
 17. A procatalyst as claimed in claim 16wherein said metal ion is an ion of Cr or Ti.
 18. A procatalyst asclaimed in claim 16 or 17 wherein said metal is additionally coordinatedto a halogen σ-ligand.
 19. A procatalyst as claimed in any one of claims16 to 18 wherein at least one of the atoms N or Z or the double bond ofthe bicyclic ring is coordinated to the metal ion.
 20. A procatalyst asclaimed in claim 19 wherein the group LIG and the atom N are coordinatedto the metal ion.
 21. An olefin polymerisation catalyst systemcomprising or produced by reaction of (1) a procatalyst as claimed inclaims 16 to 20 and (2) a cocatalyst.
 22. A process for olefinpolymerisation comprising polymerising an olefin in the presence of acatalyst system as described in claim
 21. 23. A process for thepreparation of a procatalyst, said process comprising metallating with agroup 3 to 7 transition metal a compound of formula (I)

wherein LIG, X, Y, Z and rings A₁ and A₂ are as hereinbefore defined.24. The use of a procatalyst as claimed in any one of claims 16 to 20 inolefin polymerisation.